Convertible alternating to direct current power supply and battery charging means for portable electrical equipment



United States Patent C CONVERTBLE ALTERNATING T DIRECT CUR- RENT PWERSUPPLY AND BATTERY CHARG- lNG MEANS FR PORTABLE ELECTRICAL EQUIPMENTMilton H. Peiavin, Brooklyn, N. Y., assignor to Conitecii, Ltd., NewYork, N. Y., a corporation of New York Application August 20, 1953,Serial No. 375,374

11 Claims. (Cl. 307--66) The present invention relates generally topower supplies and in particular to a combined rectified power supplyand battery Charger circuit.

An object of the present invention is the provision of an alternatingcurrent power supply which provides a direct current voltage output andwhich has a battery charging circuit whereby battery operated electricalapparatus may be connected to said direct current voltage output and thebattery thereof may be connected to the charging circuit during theperiod that said apparatus operates from said direct current voltagesupply.

ln connection with the foregoing object, provision is made for a batterycharging circuit which utilizes an inverse-temperature compensatedvoltage relay and, therefore, it is another object to provide forautomatically resetting the relay when the battery is disconnected fromthe charging circuit.

Another object of the present invention is the provision of means forautomatically resetting the inversetemperature compensated voltage relayin the event of power line failure.

A further object is the provision of means for automatically switchingthe battery from the charging circuit to the electrical apparatus whichis connected to the direct current voltage supply in the event of powerline failure, or in the event of failure in the components of therectified power supply circuit.

A still further object is the provision of an alternating current supplyhaving provision to prevent interaction between a plurality of loadssimultaneously connected thereto.

The above and other objects, features and advantages of the presentinvention will be fully understood from the following descriptionconsidered in connection with the sole illustrative drawing herein whichillustrates the best mode now contemplated by me for carrying out myinvention, which drawing illustrates a schematic circuit diagram for acombined power supply and battery charging means pursuant to the presentinvention.

Referring now in detail to the single figure of the drawing herein, thereference numeral diagrammatically indicates a unit of electricalapparatus or equipment which requires a direct current voltage supply,and the reference numeral 12 indicates a storage battery supplytherefor. As presently constructed and used, the combined power supplyand charging circuit of the present invention is used in connection withan artificial respirator of the general type shown in Patent No.2,466,108 to T. C. Huxley, ill', as well as in the copending applicationof said T. C. Huxley, Serial No. 295,181 filed June 24, 1952 andassigned to the assignee hereof, which illustrates a pumping apparatusfor the respirator which can be operated by a direct current motor. Arespirator of said type is convenient for portable use, for example,during transportation or movement of a patient who requires continuoususe of the respirator, or when a patient is out of doors or away from apower line. Under such circumstances the respirator operates from astorage battery. However,

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where an alternating current power line is available, the respirator isoperated by an alternating current power supply to provide a directcurrent voltage output therefor. lt will be readily apparent that it isquite convenient to charge the storage battery while the respirator isbeing operated from the direct current voltage output and from the samecircuit which provides said direct current voltage output. ln addition,while the respirator is operating ofi the alternating current power lineand its battery is being charged, as described, the present inventioncontemplates the provision of means to automatically connect therespirator to the battery for operation thereby in the event of failureof the alternating current power source or in any of the power supplycomponents. However, while reference is made in the drawing and in therescription to a respirator, it will be understood that a respirator isused herein purely for illustrative purposes and that the presentinvention is not limited to use with a respirator and can be used inconnection with any type of electrical equipment, `apparatus orcomponent that can operate from a direct current voltage.

The combined battery charger and power supply apparatus of the presentinvention, generally indicated by the reference numeral 11, operatespreferably from volt A. C. source, being provided with the transformer14, the secondary of which is connected to the rectifier 16 and therectifier 18 so that said rectifiers are supplied in common by thetransformer. The rectifier 18 provides. the rectified or direct-currentvoltage output supply for operating the electrical equipment 16, which,as previously indicated, ma* by way of example, be constituted by thepump motor for a portable respirator, in the present use of theappparatus. The reference numeral 15 generally indicates the circuit forproviding said direct current voltage output, which circuit includessaid rectifier 18. It will be noted that only a portion of the voltageoutput of the transformer 14 is supplied to the rectifier 18, asindicated by the taps 20 and 22 so as to provide, in the present use ofthe apparatus 11, a 24 volt directcurrent output at the rectifier 18,which is the required voltage for operating the motor of the respirator10. Said output voltage of the rectifier 18 is applied through the wires24 and 26 to the stationary contacts 2S and 30 of the relay 32 which isconnected across said wires. In the energized condition of the relay 32,said contacts 2S and 30 are closed by the movable contact elements 3dand 36, respectively, of the relay 32, which elements are connected tothe motor of the respirator unit 1t). Consequently, it will be apparentthat with the plug 33 connected to an outlet constituting a source ofalternating current voltage, the rectifier 13 supplies the directcurrent voltage for operating the electrical apparatus 19.

As previously indicated, the rectifier 16 supplies the direct currentcharging voltage for the battery 12, the charging circuit beinggenerally indicated by reference numeral 17. More specifically, it willbe noted tnat the rectifier 16, as here shown, is connected across thefull output of the transformer 1li as indicated by the taps 2i) and 4i),and it will be understood that, as now constructed the rectifier 16provides a direct current voltage output of 3() volts. The negativeoutput of the rectifier 16 is applied through the wire 42 to thestationary contact 44 of the relay 46, which relay is connected acrossthe previously mentioned wires 24 and 26 which supply the output voltageof the rectifier 1S to the unit 10, The movable contact member 4S of therelay 46 is connected by the wire 50 to the negative terminal 52 of areceptacle 54. The positive output terminal of the rectifier 16 isconnected by the wire 56 to the variable resistor or rheostat 58, whichconstitutes the high rate or high voltage charging control, and to thevariable resistor or rheostat 60, which constitutes the low rate or lowvoltage charging control, of the battery charging circuit 17. Thepositive terminal 62 of the receptacle 54 is connected by the wire 64 tothe stationary contact 66 of the relay 68, the function of which ishereinafter explained in detail. The low rate charging control 6@ isconnected to said wire 64, and the high rate charging control S isconnected to the movable contact member 70 of said relay 63. A removableplug for the receptacle 54 is indicated by the reference numeral 72.Said plug is provided with a plug terminal 74 adapted to engage thereceptacle terminal 52. A three wire cable 82 connects the plug 72 tothe battery 12, it being noted that the plug terminal 74 is connected bythe wire 84 to the positive terminal 90 of the battery, and the wires 36and 8S, for the plug terminals 7 6 and 80, respectively, are connectedto the negative terminal 92 of the battery.

As is well known to those skilled in the art, the battery voltage, onthe charging thereof, is related to the temperature of the battery. Morespecifically, the higher the battery temperature, the lower its voltageon charge, and, conversely, the lower the battery temperature, thehigher its voltage on charge. It is also well known that there is anabrupt and sharp rise in the battery voltage at about the 80 to 90 percent recharged state of the battery. Consequently, it is a commonpractice to protect the battery when it is about 80 to 90 per centrecharged, by changing the charging rate thereof, from the high to thelow charge rate, by disconnecting the circuit through the high ratecharging control and by continuing the charge under the control of thelo-w rate charging control until the desired charge is obtained. ln thisconnection, it is well known practice to utilize an inverse-temperaturecompensated voltage relay, known commercially as a TVR voltage relay,such as is fully illustrated and described in Patents Nos. 1,960,198 and2,443,968. Such a relay is schematically indicated by the referencenumeral 94. As the temperature rises, the operating voltage of the TVRrelay 94 will lower, and as the temperature lowers, the operatingvoltage of the relay will rise. The relay 94 is set to operate withinthe range of the previously mentioned abrupt voltage rise which occursduring the charge of the battery, at the 80 to 90 per cent rechargedstate thereof. The relay 94 is connected in parallel with the battery12. when the plug 72 thereof is inserted into the receptacle 5. Morespecifically, it will be noted that the relay 94 is connected throughthe wire 96 to the positive terminal 62 of the receptacle 54%, and isconnected to the negative terminal 92 by a circuit which includes thewire 9S, the switch 100, the function of which is hereinafter describedin detail, the wire lill, the movable contact member 162 of thepreviously identified relay 46, the stationary contact 10ft thereof, thewire 196, the receptacle and plug contacts 73 and 76, and the wire 86which is connected to the negative terminal h2 of the battery.Consequently, it will be apparent that the relay 94 is effectivelyconnected across the terminals 90 and 92 of the battery. Another featureof a TVR relay is the fact that once it operates, it canV be reset onlyby a momentary interruption of its coil circuit, which interruption mustbe at least one second long. As previously indicated, since the 'TVRvoltage relay normally operates in the 80 to 90 per cent recharge stateof the battery, so that the battery is thereafter continued to becharged at a low rate instead of a high rate, it will be apparent thatif the battery is then left continuously on the low rate of charge, itwould never reach a l0() per cent recharge state. In order to obviatethis condition, it is a well known practice to operate the TVR relayunder the control of a periodic recycling time switch which will resetthe relay periodically for a short period of time during the completionof the battery charge. For example, the relay may be periodically resetafter it operates to provide the low charging rate so that during oneminute of each hour the battery will be receiving its high charging rateand during the remaining 59 minutes of each hour, the battery will becharging on its low rate of charge. Such a periodic recycling timeswitch, of well known construction, is schematically indicated at1tl&`and, as here shown, is constituted by a timer 110 and thepreviously identified switch which is designated by the letters RS as arecycling switch. The timer is operated by the alternating current powersource, being connected to t.e plug 3S by the wires 112 and 114. it willbe understood that the recycling switch ltlt is a normally closed switchwhich can be operated with very small pressure and Very smalldisplacement, such as that sold under the trade name of Micro-Switch,and is operated by the timer 110 so that it is open for one minuteduring each hour of operation, and is closed during the remaining 5 9minutes of each hour of operation. In order to complete the circuit foropening the charging circuit at the righ rate control 5S when the TVRrelay 94 operates, provision is made for the previously identified relay68, one side of which is connected to the wire 112 and through thelatter to the plug 3S, the other side of the relay 68 being connectedthrough the wire 116 to the stationary contact 113 of the TVR relay 94,the movable contact member 126 of the TVR relay being connected by thewire 122 to the wire 114, and through the latter to the plug 38.Consequently, it will be apparent that during the normally closedengagement of the TVR relay contacts 11% and 124), which is the normalcondition of said contacts before the TVR relay 41 operates within thepreviously described range of the abrupt voltage rise of the battery 12,it will be apparent that the relay 63 is in energized condition and insaid condition retains the movable contact 70 in engagement with theContact 66 so that the battery is being subjected to its high chargingrate. However, when the voltage at the battery terminals rises to thevalue at which the TVR relay operates, the contact thereof disengagesthe contact 118 to open the circuit through the relay 68, which resultsin the disengagement of the contact 70, of the latter relay, from thestationary contact 66 toopen the charging circuit through the highVcharging control 53. This discontinues the high rate of charge, it beingnoted that the charging circuit remains completed through the low ratecharging control eil and the charge continues at the low or tricklecharging rate.

From the foregoing, it will be apparent that the rectifier 16 suppliesthe charging voltage for the battery 12 and the rectiiier 13 suppliesthe operating voltage for the apparatus l@ when the latter is utilizingthe alternating current line voltage as a power source. By using twoseparate rectifier-s, a separate voltage magnitude is obtained for theapparatus 1li and a separate voltage magnitude is obtained for chargingthe battery 12. As previously indicated, as now constructed, therectifier 18 supplies a 24 volt direct current supply for operating themotor of a respirator 10, and the rectifier 16 provides a higher supply,namely 30 volts, for charging the battery 12. In addition to theadvantage of a higher voltage for such purpose, as described, theutilization of two separate rectitiers also provides for voltageregulation. In this connection, it will be apparent thatthe battery 12,when being charged, is electrically isolated from the apparatus 10 sothat there is no interaction between said units and good voltageregulation is obtained. l Pursuant to another feature of the presentinvention, the TVR relay 94 is automatically reset whenever the battery12 is disconnected from the charging circuit 17. More speciiically, andas previously indicated, the coil of the TVR relay 94 is connected tothe battery terminals 90 and 92 and is energized thereby, the batteryserving to complete the circuit through the relay. Consequently,whenever the plug '72 is disconnected from the receptacle 54, fordisconnecting the battery'lZ from it-s charging circuit 17, the TVRrelay 94 is de-energized, and therefore is automatically reset, so thatwhen the plug 72 is thereafter reinserted in the receptacle S4 torecharge the battery, contacts 11S and 120 will be engaged so that thecircuit through the secondary relay 68 is closed and the high ratecharging control 58 will be in the charging circuit whereby the batterywill be subjected to its high rate of charge. In addition to theforegoing, another feature of the invention resides in the fact that theTVR relay 94 is automatically reset in the event of failure in thealternating current line voltage. In this connection, it will be noted,as previously indicated, that the relay 46 is connected across the lines24 and 26 from the rectifier 18 and when energized, closes the contacts102 and 104. Upon failure of the alternating current line voltage, itwill be apparent that the relay 46 will be de-energized to open thecircuit through the coil of the TVR relay 94 by the disengagement of thecontact 102 from the contact 104. This automatically reset-s the TVRrelay 94 so that upon resumption of the line voltage, the battery willbe charged at its high charging rate.

Pursuant to another feature of the present invention, the battery isautomatically disconnected from its charging circuit 17 and connected tooperate the electrical equipment 10, in the event of power failure inthe line voltage, and also in the event of failure in the transformer 14or in the rectifier 1S. In this connection, it will be noted, aspreviously indicated, that the relay 32 is energized by the rectifier 18and, when so energized, closes the contacts 28 and 30 thereof by meansof the movable contacts 34 and 36, respectively. Said relay is alsoprovided with the contacts 124 and 126. Contact 124 is connected by Wire128 to the positive terminal 62 of the receptacle 54 and, through theplug terminal 74, when the plug is engaged with the receptacle to thepositive battery terminal 90. The contact 126 is connected through theWire 130 to the negative terminal 52 of the receptacle 54, and throughthe plug terminal 80 to the negative terminal 92 of the battery. It willbe apparent that in the event of failure of the alternating current linevoltage, the relay 32 will be deenergized whereupon the contacts 124 and126 will be engaged by the movable contacts 34 and 36 respectively, -soas to automatically connect the apparatus to the terminals 62 and 52 ofthe receptacle 54, and through the companion terminals of the plug 72,to the negative and positive terminals of the battery 12. Similarly, inthe event of failure of either the transformer 14 or the rectifier 18,the relay 32 will be de-energized to connect the apparatus 10 across theterminals of the battery 12.

Pursuant to another feature of the invention, the relay 46 also operatesto disconnect the circuit between the rectiiier 16 and the battery 12 inthe event of failure in the alternating current line voltage. In thisconnection, as previously indicated, rectier 16 is connected to thenegative terminal 52 of receptacle 54 through wire 42; contacts 44 and48 of relay 46 and wire 50. Said contacts are engaged when the relay isenergized and when the relay is de-energized, as by failure of the linevoltage, con* tacts 44 and 48 are disengaged. This prevents the batteryfrom discharging a small reverse current through the rectifier 16. Alsoin the event of failure of rectifier 18 alone, the de-energization ofrelay 46 prevents rectifier 16 from supplying the current to therespirator as well as the charging current to the battery.

While I have shown and described the preferred embodiments of myinvention, it will be understood that various changes may be made in thepresent invention without departing from the underlying idea orprinciples of the invention within the scope of the appended claims.

Having thus described my invention, what I claim and desire to secure byLetter-s Patent, is:

l. In an alternating current power supply, a transformer, a batterycharging circuit and a direct current power supply circuit electricallyindependent of said charging circuit and energized in common therewithby said transformer, and rectifier means in each of said circuits,whereby a battery connected to said charging circuit and an electricalapparatus connected to said direct current power supply circuit will beelectrically isolated from each other.

2. In an alternating current power `supply circuit, a transformer, abattery charging circuit and a direct current power supply circuitenergized in common by said transformer, and means operable upon failureof output from said direct current supply circuit to automaticallydisconnect a load therefrom and to connect the load to the battery undercharge by said charging circuit.

3. In an alternating current power supply circuit, a transformer, abattery charging circuit and a direct cur rent power supply circuitenergized in common by said transformer, and means operable upon failureof output from said direct current supply circuit to automaticallydisconnect a load therefrom and to connect the load to the battery undercharge by said charging circuit, said means being relay means energizedby said direct current power supply circuit and operable when soenergized to complete a circuit between the load and said direct currentpower supply circuit, said relay when de-energized being operable tocomplete a circuit between the load and the battery under charge.

4. In an alternating current power supply, a battery charging circuitand a direct current power supply circuit energized in common, means toconnect a battery under charge to the output of said charging circuit,means to connect a load to the output of said direct current powersupply circuit, said load connecting means being operable to connectsaid load automatically to the battery upon failure of said directcurrent power supply circuit, and means to interrupt the charging of thebattery upon failure of said direct current power supply circuit,whereby to prevent said battery charging circuit from supplying both thebattery and the load upon failure of said direct current power supplycircuit.

5. An alternating current power supply as defined in claim 4, furthercharacterized in the provision of a first rectifier means in saidbattery charging circuit and a second rectier means in said directcurrent supply circuit, said load connecting means being relay meansenergized by said second rectifier means to connect the load to theoutput of said second rectifier' means and operable when dre-energizedto connect the load to the battery, and said interrupting means beingadditional relay means energized by said second rectifier means andoperable when de-energized to interrupt the circuit between said rstrectifier means and the battery whereby to prevent the battery fromdischarging a reverse current through said first rectifier means uponfailure of said common energization of said circuits.

6. In combination, a circuit for charging a storage battery from a powersource, said circuit having means to selectively provide a higher or alower battery char-g` ing rate, an inverse temperature-compensated relayconnected in circuit with the battery for energization by the battery,means operable by said relay at a predetermined energization thereof tocondition said selective means for said lower charging rate, and adisconnect means between said battery and each of said circuits forremoving said battery from said charging circuit and for concomitantlyde-energizing said relay means, whereby to reset the latter forconditioning said selective means for the higher charging rate uponreconnection of said battery.

7. In combination, a circuit for charging a storage battery from a powersource, said circuit having means to selectively provide a higher or alower battery charging rate, an inverse temperature-cornpensated relayconnected in a circuit with the battery for energization by the battery,means operable by said relay at a predetermined energization thereof tocondition said selective means for said lower charging rate, and adisconnect means between said battery and each of said circuits forremoving said battery from said charging circuit and for concomitantlyde-energizing said relay means, whereby to reset the latter forconditioning said selective means for 'the`higher charging rate uponreconnection of said battery, said selective charging rate meansincluding a first resistor connected in said charging circuit, a secondresistor, a second relay connected in parallel circuit with saidcharging circuit and having contacts which operate upon energization ofsaid second relay to connect said second resistor in parallel with saidirst resistor to pro vide said high charging rate, said first relayhaving contacts which normally complete the circuit for said secondrelay, and said latter contacts operating to interrupt said second relaycircuit upon said predetermined energization of said first relay,whereby to disconnect said second resistor to provide said low chargingrate.

8. In combination, a circuit for charging a storage batter;l from apower source, said circuit having means to selectively provide a higheror a lower battery charging rate, an inverse temperature-compensatedrelay connected in circuit with the battery for energization by thebattery, means operable by said relay at a predetermined energizationthereof to condition said selective means for said lower charging rate,said selective charging rate means including a first resistor connectedin said charging circuit, a second resistor, a second relay connected inparallel circuit with said charging circuit and having contacts whichoperate upon energization of said second relay to connect said secondresistor in parallel with said first resistor to provide said highcharging rate, said first relay having contacts which normally completethe circuit for said second relay, and said latter contacts operating tointerrupt said second relay circuit upon said predetermined energizationof said irst relay, whereby to disconnect said second resistor toprovide said low charging rate.

9. In combination, a circuit for charging a storage battery from a powersource, said circuit having means to selectively provide a higher or alower battery charging rate, an inverse temperature-compensated relayconnected in circuit with the battery for energization by the battery,means operable by said relay at a predetermined energization thereof tocondition said selective means for said lower charging rate, a secondrelay connected to said power source through a circuit independent ofsaid charging circuit and normally energized by said power source, andsaid second relay having contacts in circuit between said firstmentioned relay and said battery which contacts are closed in theenergized condition of said second relay, whereby to open the energizingcircuit for said first relay upon failure of said power source forconditioning said charging circuit for the higher charging rate uponresumption of said power source.

10. In an alternating current power supply, a circuit for charging abattery, a direct current power supply circuit, said charging circuithaving means to selectively provide a higher or a lower battery chargingrate, an inverse temperature-compensated relay connected in circuit withthe battery for energization by the battery, means operable by saidrelay at a predetermined energization thereof to condition saidselective means for said lower charging rate, and a second relayconnected in said direct current power supply circuit for energizationthereby, and said second relay having contacts in circuit between saidlirst mentioned relay and said battery which contacts are closed in theenergized condition of said second relay, whereby to open the energizingcircuit for said first relay upon failure of said direct current powersupply circuit for conditioning said charging circuit for the highercharging rate upon resumption of said direct current power supplycircuit.

11. In combination, a circuit for charging a storage battery from apower source, said circuit having means to selectively provide a higheror a lower battery charging rate, an inverse temperature-compensatedrelay connected in circuit with the battery for energization by thebattery, means operable by said relay at a predetermined energizationthereof to condition said selective means for said lower charging rate,a second relay connected to said power source through a circuitindependent of said charging circuit and normally energized by saidpower source, and said second relay having contacts in circuit betweensaid iirst mentioned relay and said battery which contacts are closed inthe energized condition of said second relay, whereby to open theenergizing'circuit for said rst relay upon failure of said power sourcefor conditioning said charging circuit for the higher charging rate uponresumption of said power source, said charging circuit including arectifier in circuit with said battery and said second relay havingadditional contacts in circuit between the rectiier'and the batterywhich complete said circuit in the energized condition of said secondrelay, whereby said additional contacts are operable to open the circuitbetween the battery and rectifier upon failure of said power source.

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